GRAPHS OF UPWELLING INDICES OVER THE LAST 18 MONTHS

For 15 Positions Along the North American West Coast

Solid lines denote the daily Upwelling Index. The daily indices have been
smoothed using a 3-day, 3rd order, forward-reverse Butterworth filter. The dashed curve is a biharmonic fit to the daily upwelling indices for the period 1967-1991. The shaded area around the biharmonic curve denotes one standard error, calculated for each Julian day. The yellow bars denote monthly mean of the Upwelling Indices based on the daily values. The units are metric tons per second per 100 m of coastline (or equivalently cubic meters per second per 100 meters of coastline). These units may be thought of as the average amount of water upwelled through the bottom of the Ekman layer each second along each 100 m of a straight line directed along the dominant trend of the coast on a scale of about 200 miles.